Fuel cell and electronic equipment mounting it

ABSTRACT

A fuel cell and an electronic apparatus with same mounted thereon are provided. The fuel cell includes a power generation unit provided with a conduit for an oxidant gas containing at least oxygen, a heat radiation unit connected to the power generation unit so as to radiate heat from the power generation unit, a gas flow means for causing the oxidant gas to flow in the conduit, and a cooling means driven independently from the gas flow means so as to cool the heat radiation unit. By independently controlling the driving of the gas flow means and the cooling means, the fuel cell can be driven in such a manner that the temperature of the power generation unit and the amount of water remaining in the power generation unit are regulated into preferable conditions. Furthermore, it is possible to provide a fuel cell and an electronic apparatus with the same mounted thereon in which power generation can be performed stably and various apparatuses are contained therein in a compact form.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Japanese Patent Document No.P2002-361449 filed on Dec. 12, 2002, the disclosure of which is hereinincorporated by reference.

BACKGROUND

The present invention relates to a fuel cell and an electronic apparatuswith the same mounted thereon. More particularly, the present inventionrelates to a fuel cell and an electronic apparatus with the same mountedthereon in which various apparatuses for stably performing powergeneration by a fuel cell or cells are contained in a compact form.

A fuel cell is a power generation device for generating electric powerby an electrochemical reaction between a fuel, such as hydrogen gas, andan oxidant such as oxygen contained in air. In these years, the fuelcells have been paid attention to as a power generation device free ofenvironmental pollution, since the product upon power generation thereinis water, and the use of a fuel cell as a drive power source for drivinga vehicle, for example, has been tried.

Furthermore, the application of a fuel cell is not limited to theabove-mentioned drive power source for driving automobiles, and thedevelopment of fuel cells as drive power sources for portable electronicapparatuses such as notebook type personal computers, cellular phonesand PDAs has been made vigorously. It is important for these fuel cellsto be capable of stably outputting required electric power and to havesuch size and weight as to be portable, and a variety of technicaldevelopments have been carried out vigorously.

In addition, the quantity of electric power outputted from a fuel cellcan be enhanced by joining a plurality of power generation cells (unitcells). For example, there has been developed a fuel cell in which ajoint body having electrodes provided on both sides of a solid statepolymer electrolyte membrane is clamped between separators to form apower generation cell, and such power generation cells are laminated toform a stack structure.

Meanwhile, at the time of generating electric power by the fuel cellconfigured as above, it is necessary for the solid state polymerelectrolyte membrane to conduct protons therethrough and it is importantfor the solid state polymer electrolyte membrane to be moistenedappropriately.

However, the power generation reaction in the fuel cell is an exothermicreaction, and the portion where the power generation reaction occursvigorously tends to be brought to a high temperature. Therefore, thereare cases in which the amount of water contained in the solid statepolymer electrolyte membrane is decreased attendant on the driving ofthe fuel cell, with the result of a trouble in stable power generationin the fuel cell.

On the other hand, water is produced by the electrochemical reaction atthe time of power generation. Where water is accumulated in the conduitfor a fuel gas formed in the separator, the conduit may be clogged withwater to hamper smooth flow of the fuel gas in the conduit. Where smoothflow of the fuel gas is not achieved in the conduit, it is difficult tosufficiently supply the fuel gas into the plane of the joint body, sothat the power generation by the fuel cell cannot be performedsatisfactorily.

The above-mentioned two problems show that it is difficult tosimultaneously achieve both the restraint of the temperature rise in thefuel cell at the time of power generation by the fuel cell and thecontrol of the amount of water contained in the fuel cell. Therefore,there is a demand for a technology by which these problems can be solvedat the same time. Particularly, in the fuel cell having the stackstructure, there is a demand for a technology by which a smooth flow ofthe fuel gas in the conduits formed in a plurality of separators isachieved, and oxygen-containing air is taken in from the exterior of thefuel cell so as to bring the joint body constituting the fuel cell intothe state of being moistened appropriately, making it possible to stablyoutputting the required electric power.

Besides, where a fuel cell is used for driving a portable electronicapparatus, it is desirable that the fuel cell is also portable, andthere is a demand for a fuel cell which is capable of stable powergeneration and which has been reduced in size.

SUMMARY

The present invention has been made in consideration of theabove-mentioned problems. Accordingly, the present invention provides afuel cell and an electronic apparatus with the same mounted thereon bywhich electric power can be generated stably and in which variousapparatuses for driving the fuel cell are contained in a compact form.

According to an embodiment of the present invention, there is provided afuel cell including: a power generation unit provided with a conduit foran oxidant gas containing at least oxygen; a heat radiation unitconnected to the power generation unit so as to radiate heat from thepower generation unit; a gas flow means for causing the oxidant gas toflow in the conduit; and a cooling means driven independently from thegas flow means so as to cool the heat radiation unit. By such a fuelcell as this, it is possible to independently drive the gas flow meansand the cooling means, thereby performing accurately the restraint oftemperature rise in the power generation unit and the control of theamount of water contained in the power generation unit, and permittingthe power generation unit to stably generate electric power.

The above-mentioned fuel cell is characterized in that the powergeneration unit has a joint body including a conductor having ionicconductivity and electrodes opposed to each other with the conductortherebetween, and separators clamping the joint body therebetween. Withmoisture sufficiently absorbed in the conductor, it is possible to forma fuel cell which can perform the power generation reaction at the timeof power generation without any trouble and which has a small size and ahigh output.

Further, the above-mentioned fuel cell is characterized in that theconductor is a proton conductor.

Furthermore, the above-mentioned fuel cell is characterized in that theseparators each have a heat transfer portion extending from the insideof the separator to the heat radiation unit. With such a heat transferportion, the heat generated upon the power generation reaction can bespeedily transmitted from the power generation unit to the heatradiation unit, and the temperature rise in the power generation unitcan be restrained.

In addition, the above-mentioned fuel cell is characterized in that theseparators each has a water suction means for sucking and removing waterfrom the conduit. With such a water suction means, water accumulated inthe conduit for flow of the oxidant gas can be sucked out, and theoxidant gas can be made to flow smoothly in the conduit.

Furthermore, the above-mentioned fuel cell is characterized in that thepower generation unit has a stack structure in which the joint body andthe separators are laminated. With the stack structure thus formed, itis possible to enhance the output power of the power generation unit andto output the required electric power.

Further, the above-mentioned fuel cell is characterized in that theseparators each have an in-plane conduit for supplying the fuel into theplane where the separator and the joint body make contact. The fuel issupplied to roughly the entire surface of the joint body by the in-planeconduit, and power generation can be performed efficiently.

Furthermore, the above-mentioned fuel cell is characterized in that theseparators are each provided with a supply hole for supplying the fuelinto the in-plane conduit, and a discharge hole for discharging the fuelfrom the in-plane conduit. With such a supply hole, it is possible tosupply the fuel to each separator and to discharge the fuel after thepower generation reaction from the in-plane conduit.

Further, the above-mentioned fuel cell is characterized in that, betweenthe adjacent separators, the supply holes are connected to each other toform a supply passage for supplying the fuel to the separators, and thedischarge holes are connected to each other to form a discharge passagefor discharging the fuel from the separators. In the stack structure inwhich the joint body and the separators are laminated, it is possible tosupply the fuel gas at a stroke to the power generation unit through thesupply passage, and to discharge the fuel gas after the power generationreaction through the discharge passage.

Furthermore, the above-mentioned fuel cell is characterized in that thesectional area of a connection portion where the in-plane conduit isconnected to the supply passage is smaller than the sectional area ofthe in-plane conduit. With such a connection portion, it is possible todischarge water accumulated in the in-plane conduit at the time ofdischarging the fuel from the in-plane conduit.

In addition, the above-mentioned fuel cell is characterized in that thesectional area of a connection portion where the in-plane conduit isconnected to the discharge passage is smaller than the sectional area ofthe in-plane conduit. With such a connection portion, it is possible todischarge water accumulated in the in-plane conduit at the time ofdischarging the fuel from the in-plane conduit.

Besides, the above-mentioned fuel cell is characterized in that thesectional area of a connection portion where the in-plane conduit isconnected to the supply passage is smaller than the sectional area of aconnection portion where the in-plane conduit is connected to thedischarge passage. With such a connection portion, it is possible todischarge water accumulated in the in-plane conduit at the time ofdischarging the fuel from the in-plane conduit.

Further, the above-mentioned fuel cell is characterized by having awater discharge means for discharging water from the in-plane conduit bygenerating a difference in pressure on the water between the supplypassage side and the discharge passage side, in the in-plane conduit inwhich the water is accumulated. With such a water discharge means, thewater accumulated in the in-plane conduit is discharged from thein-plane conduit by the pressure difference, so that the fuel cansmoothly flow in the in-plane conduit.

The above-mentioned fuel cell is characterized in that the waterdischarge means opens a part of the discharge passage to the atmosphereso as to generate a pressure difference and thereby to discharge thewater from the in-plane conduit. With such a water discharge means, apressure difference is instantaneously generated in the in-plane conduitby opening the discharge passage to the atmosphere, and the water can bedischarged from the in-plane conduit by the pressure difference.

In addition, the fuel cell according to the present invention ischaracterized in that the cooling means causes the gas stagnating in thevicinity of at least the heat radiation unit to flow, thereby releasingheat from the heat radiation unit. The gas made to flow releases theheat sequentially from the heat radiation unit, whereby the temperaturerise in the heat generation unit can be restrained.

Besides, the fuel cell according to the present invention ischaracterized by having a detection means for detecting an environmentalcondition for controlling the driving of the gas flow means and thecooling means. With the gas flow means and the cooling means drivenaccording to the environmental condition(s), the power generation unitcan be driven under the condition where stable power generation isperformed.

Further, the above-mentioned fuel cell is characterized in that thedetection means detects at least temperature and/or humidity as theenvironmental condition(s). With the temperature and/or humiditydetected, it is possible to calculate the temperature of the powergeneration unit and the amount of water remaining in the powergeneration unit, and to perform power generation under preferableconditions.

In addition, the above-mentioned fuel cell is characterized in that thedetection means are arranged at such positions as to be capable ofdetecting the temperature and humidity of the oxidant gas supplied tothe power generation unit, the temperature and humidity of the oxidantgas discharged from the power generation unit, and the temperature ofthe power generation unit. With the temperature and/or humidity detectedat these portions in the fuel cell, it is possible to accuratelycalculate the amount of water remaining in the power generation unit.

Furthermore, the above-mentioned fuel cell is characterized by having acontrol substrate supporting thereon a control circuit for controllingthe driving of at least the gas flow means and the cooling means on thebasis of the environmental condition(s). With such a control circuit, itis possible to control the driving of the gas flow means and the coolingmeans and thereby to permit the power generation unit to generateelectric power under preferable conditions.

In addition, the above-mentioned fuel cell is characterized in that thedriving of the gas flow means and the cooling means is controlledaccording to the amount of water contained in the power generation unitwhich is calculated based on the environmental condition(s) and thequantity of electric power generated by the power generation unit. Withsuch gas flow means and cooling means of which the driving is controlledin this manner, it is possible to bring the amount of water remaining inthe power generation unit into a preferable condition, and to performstable power generation.

Besides, the fuel cell according to the present invention ischaracterized by having a fuel supply means for supplying a fuel forreaction with the oxidant gas from a fuel storage unit to the powergeneration unit at the time of driving the power generation unit. Withsuch a fuel supply means, the fuel can be supplied from the fuel gasstorage unit provided separately from the power generation unit to thepower generation unit.

In addition, the fuel cell according to the present invention ischaracterized by having a pressure control means for controlling thepressure of the fuel gas supplied to the power generation unit. Bysupplying the fuel while controlling the pressure of the fuel, it ispossible for the power generation unit to perform stable powergeneration.

According to the present invention, there is provided a fuel cellincluding: a power generation unit provided in its side surface with anopening portion of a conduit for an oxidant gas containing at leastoxygen; and a heat radiation unit connected to the power generation unitso as to radiate heat from the power generation unit. A gas flow meansfor causing the oxidant gas to flow in the conduit is disposed along aside surface of the power generation unit, and a cooling means forcooling the heat radiation unit is disposed along the side surfaceadjacently to the gas flow means. With such a fuel cell, the apparatusescontained in the fuel cell can be disposed in a compact form, theoxidant gas can be made to flow efficiently, and required powergeneration can be stably performed in a small-sized fuel cell.

The above-mentioned fuel cell is characterized in that the fuel cell hasa casing for covering at least the power generation unit, the heatradiation unit, the gas flow means, and the cooling means. With such acasing, it is possible to protect the various apparatuses arranged inthe fuel cell from the exterior, and to control the flow of air in thefuel cell.

In addition, the above-mentioned fuel cell is characterized in that thegas flow means sucks in the oxidant gas through an opening portion, anddischarges the oxidant gas through a first exhaust port provided in thecasing, thereby causing the oxidant gas to flow in the conduit. Withsuch a gas flow means, it is possible to cause the oxidant gas to flowefficiently in the fuel cell, and to perform stable power generation.

Further, the above-mentioned fuel cell is characterized in that the gasflow means sucks the oxidant gas into the fuel cell through a firstintake port provided in the casing so as thereby to form a flow of theoxidant gas independent from the flow of the oxidant gas generated bythe cooling means. With the oxidant gas sucked in through the firstintake port, the oxidant gas can be made to flow, separately from theflow of the oxidant gas generated by the cooling means.

Furthermore, the above-mentioned fuel cell is characterized in that thefirst intake port is provided at a position opposed to the first exhaustport, and the gas flow means is disposed between the first intake portand the first exhaust port. With the first intake port, the firstexhaust port and the gas flow means arranged as such positions, the flowof the oxidant gas supplied to the power generation unit and the flow ofthe oxidant gas for cooling can be made to be separate flows.

In addition, the fuel cell according to the present invention ischaracterized in that the cooling means exhausts the oxidant gas througha second exhaust port provided in the casing to thereby cause theoxidant gas to flow in the vicinity of the heat radiation unit. Withsuch a cooling means, it is possible for the flowing oxidant gas torelease heat sequentially from the heat radiation unit and thereby torestrain the temperature rise in the power generation unit.

The above-mentioned fuel cell is characterized in that the cooling meanssucks the oxidant gas into the fuel cell through a second intake portprovided in the casing. With such a cooling means, it is possible toform a flow different from the flow of the oxidant gas caused by the gasflow means.

Further, the above-mentioned fuel cell is characterized in that thesecond intake port is provided at a position opposed to the secondexhaust port, and the cooling means is disposed between the secondintake port and the second exhaust port. With the second intake port,the second exhaust port and the cooling means arranged in this manner,it is possible to cause the oxidant gas to flow smoothly for releasingheat from the heat radiation unit.

The fuel cell according to the present invention is characterized inthat the opening portion is tapered so as to be narrowed along the depthdirection of the conduit for the oxidant gas. With such an openingportion, it is possible to reduce the conduit resistance at the time ofcausing the oxidant gas to flow in the conduit for the oxidant gas, andto permit the oxidant gas to flow smoothly.

The above-mentioned fuel cell is characterized in that the opening widthof the opening portion is greater than the conduit width of the conduitfor the oxidant gas. With such an opening width, it is possible toreduce the conduit resistance at the time of causing the oxidant gas toflow in the conduit.

Further, the above-mentioned fuel cell is characterized in that theopening width is broader than the conduit width in the sidewaysdirection and/or the longitudinal direction. With the opening portionhaving such an opening width, it is possible to further reduce theconduit resistance.

In addition, the fuel cell according to the present invention ischaracterized by having detection means for detecting an environmentalcondition for controlling the driving of the gas flow means and thecooling means. With the gas flow means and the cooling means drivenaccording to the environmental condition(s), power generation can beperformed stably.

Further, the above-mentioned fuel cell is characterized in that thedetection means detect(s) at least temperature and/or humidity as theenvironmental condition(s). With temperature and/or humidity detected,it is possible to calculate the temperature of the power generation unitand the amount of water contained in the power generation unit, and toperform power generation under favorable conditions.

Furthermore, the above-mentioned fuel cell is characterized in that thedetection means are arranged respectively at such positions as to becapable of detecting the temperature and humidity of the oxidant gassupplied to the power generation unit, the temperature and humidity ofthe oxidant gas discharged from the power generation unit, and thetemperature of the power generation unit. With temperature and/orhumidity detected at these positions, it is possible to accuratelycalculate the amount of water remaining in the power generation unit.

In addition, the above-mentioned fuel cell is characterized by having acontrol substrate supporting thereon a control circuit for controllingthe driving of at least the gas flow means and the cooling means on thebasis of the environmental conditions. With such a control substrate, itis possible to control the gas flow means and the cooling means.

The fuel cell according to the present invention is characterized inthat a water discharge means for discharging water from the conduit forthe fuel gas supplied to the power generation unit for reaction with theoxidant gas is disposed along an end face of the power generation unit.With the water discharge means disposed in this manner, it is possibleto discharge an excess of water accumulated in the fuel cell, and toefficiently use the space in the fuel cell.

In addition, the fuel cell according to the present invention ischaracterized in that a fuel gas supply means for supplying the fuel gasfrom a fuel gas storage unit to the power generation unit at the time ofdriving the power generation unit is disposed along an end face of thepower generation unit. With such a fuel gas supply means, it is possibleto supply the fuel gas from the fuel gas storage unit providedseparately from the power generation unit to the power generation unit,and to efficiently use the space in the fuel cell.

According to the present invention, there is provided an electronicapparatus including a fuel cell. The fuel cell includes: a powergeneration unit provided with a conduit for an oxidant gas containing atleast oxygen; a heat radiation unit connected to the power generationunit so as to radiate heat from the power generation unit; a gas flowmeans for causing the oxidant gas to flow in the conduit; and a coolingmeans driven independently of the gas flow means so as to cool the heatradiation unit. The electronic apparatus is driven by being suppliedwith electric power from the fuel cell. With such an electronicapparatus, the electronic apparatus can be driven stably.

In addition, according to the present invention, there is provided anelectronic apparatus including a fuel cell. The fuel cell includes: apower generation unit provided in its side surface with an openingportion of a conduit for an oxidant gas containing at least oxygen; anda heat radiation unit connected to the power generation unit so as toradiate heat from the power generation unit. A gas flow means forcausing the oxidant gas to flow in the conduit is disposed along a sidesurface of the power generation unit, and a cooling means for coolingthe heat radiation unit is disposed along the side surface adjacently tothe gas flow means, and the electronic apparatus is driven by beingsupplied with electric power from the fuel cell. With such an electronicapparatus, the electronic apparatus can be driven stably, and it ispossible to provide a portable electronic apparatus.

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the following DetailedDescription and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an exploded perspective view showing the structure of a fuelcell according to an embodiment of the present invention

FIG. 2A is a side view showing the structure of a casing constitutingthe fuel cell according to an embodiment of the present invention.

FIG. 2B is a side view showing another side surface showing thestructure of the casing constituting the fuel cell according to anembodiment of the present invention.

FIG. 2C is an end view showing the structure of the casing constitutingthe fuel cell according to an embodiment of the present invention.

FIG. 2D is an end view showing another end surface showing the structureof the casing constituting the fuel cell according to an embodiment ofthe present invention.

FIG. 3 is a perspective view showing the general appearance of a powergeneration unit constituting the fuel cell according to an embodiment ofthe present invention.

FIG. 4 is an exploded perspective view showing a part of the powergeneration unit constituting the fuel cell according to an embodiment ofthe present invention.

FIG. 5A is a plan view showing the structure of the face side of aseparator showing the structure of the separator constituting the fuelcell according to an embodiment of the present invention.

FIG. 5B is a plan view showing the structure on the back side of theseparator showing the structure of the separator constituting the fuelcell according to an embodiment of the present invention.

FIG. 6A is a sectional view of a separator showing the structure of ananother example of the separator preferable for the fuel cell accordingto an embodiment of the present invention.

FIG. 6B is an essential part sectional view showing the sectionalstructure of an end portion of a separator showing a further example ofthe separator preferable for the fuel cell according to an embodiment ofthe present invention.

FIG. 7A is a plan view of an upper-side plate-like portion showing yetanother example of the separator preferable for the fuel cell accordingto an embodiment of the present invention.

FIG. 7B is a plan view showing the condition where a heat transferportion is fitted into a lower-side plate-like portion showing a stillfurther example of the separator preferable for the fuel cell accordingto an embodiment of the present invention.

FIG. 7C is a plan view, as viewed from the back side, of the lower-sideplate-like portion showing still another example of the separatorpreferable for the fuel cell according to an embodiment of the presentinvention.

FIG. 8 is a plan view showing the structure of the fuel cell accordingto an embodiment of the present invention.

FIG. 9 illustrates a control method for controlling the temperature ofthe power generation unit and the amount of water remaining in the powergeneration unit in the fuel cell according to an embodiment of thepresent invention.

FIG. 10 illustrates a specific structure of the separator according tothe present embodiment, and is a plan view sowing the structure of theseparator as viewed from the face side.

FIG. 11 illustrates a specific structure of the separator according tothe present embodiment, and is a side view showing the structure of theseparator as viewed from a lateral side.

FIG. 12 illustrates a specific structure of the separator according toan embodiment of the present embodiment, and is a plan view showing thestructure of the separator as viewed from the back side.

FIG. 13 is a plan view showing a specific structure of a fuel cellapparatus according to an embodiment of the present embodiment.

FIG. 14 is a side view showing a specific structure of the fuel cellapparatus according to an embodiment of the present embodiment.

DETAILED DESCRIPTION

Now, a fuel cell and an electronic apparatus according to an embodimentwill be described in detail below referring to the drawings.

As shown in FIG. 1, the fuel cell 1 includes a casing 10, a controlsubstrate 20, a power generation unit 30, a cooling fan 51, air supplyfans 52, 53, a hydrogen purge valve 54, a regulator 55 and a manualvalve 56. In addition, the fuel cell 1 receives hydrogen gas suppliedfrom a hydrogen occlusion cartridge 60 containing hydrogen gas occludedtherein, and performs power generation.

As shown in FIG. 1 and FIGS. 2A to 2D, the casing 10 is roughlyrectangular parallelepiped in outside shape, has a hollow inside so asto cover apparatuses mounted on the fuel cell 1, and is opened on itsbottom side. The casing 10 is provided with exhaust ports 11, 12 and 13,and intake ports 14, 15, and an end portion of the upper surface of thecasing 10 is an inclined surface extending toward a side surfaceprovided with the exhaust ports 11, 12 and 13. Referring to FIG. 2A, theexhaust ports 11 and the exhaust ports 12, 13 are adjacently formed inone side surface of the casing 10, and air made to flow in the fuel cell1 for cooling the power generation unit 30 and air after the powergeneration reaction by the power generation unit 30 are dischargedrespectively through the exhaust ports 11 and the exhaust ports 12, 13.The exhaust ports 11 are air outlets through which air for releasingheat from radiation fins 33 (described later) is to be discharged.Further, the exhaust ports 11 are opened in a roughly rectangular shapein the side surface of the casing 10, and are formed in plurality in thevertical direction. In addition, the exhaust ports 12, 13 are airoutlets through which air supplied to the power generation unit 30 atthe time of power generation in the power generation unit 30 is to bedischarged, are opened in rectangular shape in the side surface of thecasing 10, and are formed in plurality in the vertical direction alongthe exhaust ports 11. Besides, the exhaust ports 11, 12, 13 are formedso that their longitudinal sizes are sequentially shortened along theupward and downward directions of the side surface of the casing 10.

Further, referring to FIG. 2B, the intake ports 14, 15 are formed in aside surface opposite to the side surface of the casing 10 in which theexhaust ports 11 and the exhaust ports 12, 13 are formed, of the casing10, and air for cooling the power generation unit 30 and air containingoxygen served to the power generation reaction by the power generationunit 30 are taken through the intake ports 14, 15 into the fuel cell 1.The intake ports 14 are air intake ports through which air for releasingheat from the radiation fins 33 (described later) is to be taken intothe fuel cell 1, are opened in a roughly rectangular shape in the sidesurface of the casing 10, and are formed in plurality in the verticaldirection. In addition, the intake ports 15 are air intake ports fortaking in air supplied to the power generation unit 30 at the time ofpower generation by the power generation unit 30, are similarly openedin a roughly rectangular shape in the side surface of the casing 10, andare formed in plurality in the vertical direction along the intake ports14.

Further, as shown in FIGS. 1, 2C and 2D, one end face of the casing 10can be provided with connection holes 16 through which wires fortransmission of various signals between the fuel cell 1 and the exteriorare to be passed. Furthermore, the other end face can also be providedwith required connection holes 18.

In addition, as shown in FIG. 1, the control substrate 20 is providedwith a control circuit for controlling the apparatuses constituting thefuel cell 1, and the control substrate 20 is disposed on the upper sideof the power generation unit 30. The details of the control circuit arenot shown in the figure. For example, commands concerning the control ofthe driving of the cooling fan 51 and the air supply fans 52, 53, or acontrol circuit for opening and closing operations of the hydrogen purgevalve 54, a voltage conversion circuit such as a DC/DC converter forraising the voltage outputted from the power generation unit 30, andfurther commands concerning the driving of various apparatuses bypicking up various environmental conditions such as temperature andhumidity detected by sensors (described later) can be performed bycircuits mounted on the control substrate 20. Besides, while the controlsubstrate 20 is disposed in the fuel cell 1 in the fuel cell 1 accordingto this embodiment, the control substrate 20 may be disposed in theexterior of the fuel cell 1; for example, various electronic apparatusessupplied with electric power for driving from the fuel cell 1 mayinclude the control substrate 20.

Now, the power generation unit 30 will be described in detail belowreferring to FIGS. 1, 3, 4, 5A and 5B. As shown in FIGS. 1 and 3, thepower generation unit 30 has a roughly rectangular parallelepiped shape,wherein a part of the side surface opposite to the side surface 39fronting on the cooling fan 51 and the air supply fans 52, 53 is cut outin a rectangular shape along the vertical direction of the powergeneration unit 30, and the power generation unit 30 is placed on a base57. In addition, the cooling fan 51 and the air supply fans 52, 53 areadjacently disposed along the side surface 39 of the power generationunit 30. The cooling fan 51 thus disposed radiates heat from theradiation fins 33. Besides, the air supply fans 52, 53 are so disposedas to front on opening portions 34, and air is made to flow in the powergeneration unit 30 through the opening portions 34.

In addition, the power generation unit 30 in this embodiment has jointbodies 32 sandwiched between nine separators 31, and eight powergeneration cells for performing power generation are connected in serieswith each other. Each of the power generation cells can output a voltageof about 0.6 V. Therefore, the power generation unit 30 as a whole canoutput a voltage of 4.8 V. In addition, the power generation unit 30 canpass a current of about 2 A, and the output power is ideally 9.6 W; dueto the power conversion efficiency (electronic power for accessories,step-up efficiency) of the control circuit, the actual output power isabout 6.7 W, which is about 70% of the ideal output power. However, theoutput power can be further enhanced, by regulation of the amount ofwater contained in the joint bodies 32 or smooth supply of hydrogen gasto the power generation unit 30 as will be described later. In addition,the number of the power generation cells constituting the powergeneration unit 30 is not limited to eight in this embodiment, and thepower generation unit 30 may be composed of a required number of powergeneration cells according to the output power necessary for driving thevarious electronic apparatuses. The opening portions 34 formed in theseparators 31 front on the side surface 39 of the power generation unit30, and the side surface on the opposite side of the side surface 39 ofthe power generation unit 30 is also provided with opening portions 40corresponding respectively to the opening portions 34, as will bedescribed later. Supply and exhaust of air containing oxygen to and fromthe power generation unit 30 are performed by way of the openingportions 34 and the opening portions 40 fronting on the side surface onthe opposite side of the side surface 39 on which the opening portions34 front.

Now, the power generation unit 30 will be described more in detailbelow, referring to FIGS. 4, 5A and 5B. As shown in FIG. 4, the jointbody 32 sandwiched between the separators 31 is composed of a solidstate polymer electrolyte membrane 36 showing ionic conductivity whenmoistened, and electrodes 37 clamping the solid state polymerelectrolyte membrane 36 therebetween. Further, a sealing member 35 forsealing between the separator 31 and the joint body 32 upon formation ofa stack structure is disposed near the peripheral edges of the jointbody 32. It suffices for the sealing member 35 to be formed from amaterial which can sufficiently insulate the peripheral portion of theseparator 31 and the peripheral portion of the joint body 32 from eachother. As the solid state polymer electrolyte membrane 36, there can beused, for example, a sulfonic acid-based solid polymer electrolytemembrane. As the electrode 37, an electrode supporting thereon acatalyst such as platinum for accelerating the power generation reactionmay be used. The power generation cell constituting the power generationunit 30 is composed of two separators 31 and the joint body 32sandwiched between the separators 31; for example, two power generationcells 50 to be connected in series with each other are shown in FIG. 4.

Further, as shown in FIGS. 4, 5A and 5B, the separator 31 constitutingthe power generation unit 30 includes a conduit 43, a conduit 38 formedon the back side of the surface provided with the conduit 43 of theseparator 31, a supply hole 42 and a discharge hole 41 connected to theconduit 43, a connection portion 45 for connection between the conduit43 and the supply hole 42, a connection portion 46 for connectionbetween the conduit 43 and the discharge hole 41, and a radiation fin33.

As shown in FIG. 5A, the conduit 43 is an in-plane conduit for causinghydrogen gas as a fuel gas to flow in the plane of the separator 31. Theconduit 43 is so formed as to meander in the surface of the separator 31for enhancing the efficiency of the power generation reaction, and is soshaped as to supply the hydrogen gas to the whole part of the electrode37. The supply hole 42 is a hydrogen gas conduit in supplying thehydrogen gas from a hydrogen gas storage unit such as the hydrogenocclusion cartridge 60 provided in the exterior of the power generationunit 30 into the conduit 43. The connection portion 45 connects theconduit 43 and the supply hole 42 to each other, for supplying thehydrogen gas into the conduit 43. On the other hand, the connectionportion 46 connects the conduit 43 and the discharge hole 41 to eachother, for discharging the hydrogen gas after the power generationreaction from the conduit 43. In the separator 31 in this embodiment,the sectional areas of the connection portions 45, 46 are smaller thanthe sectional area of the conduit 43 upon formation of the stackstructure from the separators 31 and the joint bodies 32; for example,the widths of the connection portions 45, 46 are smaller than the widthof the conduit 43. Further, the width of the connection portion 45 issmaller than the width of the connection portion 46, and the width ofthe conduit 43 is smaller on the inlet side than on the outlet side.

In addition, the supply hole 42 and the discharge hole 41 are connectedbetween the separators 31 which are laminated upon formation of thestack structure, for forming a supply passage for supplying the hydrogengas to each separator 31 and a discharge passage for discharging thehydrogen gas after power generation. When water is accumulated in theconduit 43, the discharge passage is opened to the atmosphere by thehydrogen purge valve 54 which will be described later, whereby apressure difference is generated in the water accumulated in the conduit43 between the supply passage side and the discharge passage side, andthe water can be discharged by the pressure difference. Further, evenwhen water is accumulated in the conduit 43 of an arbitrary separator 31upon formation of the stack structure, a pressure difference can beinstantaneously generated in only the conduit 43 in which the water hasbeen accumulated, whereby the water can be discharged and the hydrogengas can be stably supplied to the power generation unit 30.

Further, as shown in FIG. 5B, the conduits 38 are formed on the backside of the surface provided with the conduit 43 of the separator 31,and constitutes passages for causing air containing oxygen to flow intothe conduits 38. The conduits 38 are so formed as to extend in the widthdirection of the separator 31, are opened at side edge portions of theseparator 31, and are formed in plurality along the longitudinaldirection of the separator 31. In addition, oxygen-containing air issupplied and exhausted into and from the conduits 38 through openingportions 34, 40 by which the conduits 38 are opened respectively at endportions of the separator 31. As in this embodiment, the widths of theopening portions 34, 40 are set larger than the width of the conduits38. Further, the width of the conduits 38 is narrowed in a taper formalong the directions from the opening portions 34, 40 toward the depthof the conduit 38, whereby conduit resistance against air can be reducedso that air can flow smoothly at the time of intake of air into theconduit 38 or discharge of air from the conduit 38. In addition, theopening widths in the height direction of the opening portions 34, 40are also set greater than that of the conduit 38, and the opening widthsare narrowed in a taper form along the depth direction of the conduit 38in the longitudinal direction and the sideways direction of the openingportions 34, 40, whereby the conduit resistance can be further reduced.Besides, a water-absorptive material having a water-absorbing propertyis disposed in the conduits 38, and the water-absorptive material isdrawn out to the exterior of the separator 31, whereby water accumulatedin the conduits 38 can be sucked out to the exterior of the separator31.

Besides, in the fuel cell 1, a separator 70 having a structure as shownin FIGS. 6A and 6B can also be used. FIG. 6A is a sectional view showingthe structure of the separator 70, in which the separator 70 includes anupper-side plate-like portion 71, a heat transfer portion 72 and alower-side plate-like portion 73, with a sealing member 74 clampedbetween the upper-side plate-like portion 71 and the lower-sideplate-like portion 73 so as to prevent the fuel gas from leaking fromthe conduits. In addition, the sealing member 74 may be formed of amaterial higher in thermal conductivity than the material constitutingthe upper-side plate-like portion 71 and the lower-side plate-likeportion 73, whereby the heat-radiating effect for radiating heat fromthe separator 70 can be enhanced. As the sealing member 74, a sealingmember having a member with a high thermal conductivity embedded in aresin is preferably used; for example, such a sealing member asCHO-THERM (commercial name of a product by Taiyo wire cloth co., Ltd.)can be used.

The heat transfer portion 72 is formed to extend to the radiation fin75, for radiating the heat upon power generation from the separator 70.Further, the heat transfer portion 72 is formed of a material higher inthermal conductivity than the material constituting the upper-sideplate-like portion 71 and the lower-side plate-like portion 73, wherebythe heat-radiating characteristics of the separator 70 can be enhanced.As the material constituting the heat transfer portion 72, there can beused, for example, copper, which is a metal having a comparatively highthermal conductivity. Further, oxygen-free copper enhanced in corrosionresistance and a copper plate which has been surface treated to enhancecorrosion resistance may also be used. The lower-side plate-like portion73 is provided with conduit 79 extending in the direction perpendicularto the plane of the drawing, as conduits in which oxygen-containing airflows. Besides, as shown in FIG. 6B, the sealing member 74 is sandwichedbetween the upper-side plate-like portion 71 and the lower-sideplate-like portion 73 at end portions of the separator 70, whereby theheat transfer portion 72 is sealed from the exterior, and the heattransfer portion 72 is restrained from deterioration by the powergeneration reaction.

FIGS. 7A to 7C are plan views of the upper-side plate-like portion 71,the heat transfer portion 72 and the lower-side plate-like portion 73which constitute the separator 70. As shown in FIG. 7A, the upper-sideplate-like portion 71 is provided with a conduit 78 for flow of hydrogengas. The conduit 78 is formed to meander in the plane so as to permitthe hydrogen gas to flow over the entire area of the plane. In addition,the upper-side plate-like portion 71 is provided with a supply hole 77 afor supplying the hydrogen gas into the conduit 78 and a discharge hole76 a for discharging the hydrogen gas after the power generationreaction. In addition, as shown in FIG. 7B, the heat transfer portion 72is roughly plate-like, and is fitted into the lower-side plate-likeportion 73. The heat transfer portion 72 is extended to a radiation fin75, to radiate heat from the separator 70. Further, the sealing member74 is disposed at an end portion of the lower-side plate-like portion 73so as to insulate the heat transfer portion 72 from the exterior, andthe heat transfer portion 72 is sandwiched by the lower-side plate-likeportion 73 and the upper-side plate-like portion 71 to form theseparator 70 as an integral body. In the lower-side plate-like portion73, the sealing member 74 is provided with a supply hole 77 b and adischarge hole 76 b matched in position to the supply hole 77 a and thedischarge hole 76 a. Further, the lower-side plate-like portion 73 arealso provided with hole portions matched to the supply holes 77 a, 77 band the discharge holes 76 a, 76 b, whereby a supply hole and adischarge hole which are integrated upon assembly of the separator 70can be formed. Furthermore, as shown in FIG. 7C, a conduit 79 for flowof oxygen-containing air is provided on the back side of the lower-sideplate-like portion 73. Also, a supply hole 77 c for supplying hydrogengas into the conduit 78 and a discharge hole 76 c for discharging thehydrogen gas are provided.

Now, the flow of air supplied and exhausted by the fuel cell 1 in thisembodiment will be described in detail below, referring to FIG. 8. Asshown in FIG. 8, the fuel cell 1 has the cooling fan 51 and the airsupply fans 52, 53 adjacently disposed along the side surface 39, onwhich the opening portions 34 front, of the power generation unit 30, ashas been described above. Further, the fuel cell 1 has a temperaturesensor 64 for detecting the temperature of air taken in from theexterior of the fuel cell 1 by the cooling fan 51 and a humidity sensor65 for detecting the humidity of the air, and a temperature sensor 61for detecting the temperature of air discharged from the powergeneration unit 30 by the air supply fans 52, 53 and a humidity sensor62 for detecting the humidity of the air. In addition, the powergeneration unit 30 has a temperature sensor 63 for detecting thetemperature of the power generation unit 30.

As indicated by arrows in the figure, the cooling fan 51 causes the airtaken in through the intake ports 14 to flow from the intake ports 14 tothe exhaust ports 11, and discharges the air to the exterior of the fuelcell 1. The cooling fan 51 is disposed between the intake ports 14 andthe exhaust ports 11, and the radiation fin 33 disposed between thecooling fan 51 and the intake ports 14 radiates heat by the function ofthe air made to flow by the cooling fan 51. In addition, the flow of theair is not limited to the vicinity of the radiation fin 33, and the airmay be made to flow in the entire region of the inside of the fuel cell1 to thereby cool the power generation unit 30.

The air supply fans 52, 53 causes air to flow to the intake ports 15,the power generation unit 30 and the exhaust ports 12, 13. The airsupply fans 52, 53 causes the air taken in through the intake ports 15to flow to the power generation unit 30, and discharges the airdischarged after the power generation reaction in the power generationunit 30 to the exterior of the fuel cell 1 through the exhaust ports 12,13. The power generation unit 30 is provided with the conduit 38 and theopening portions 34, 40 as has been described above referring to FIGS.3, 5A and 5B, and the air supply fans 52, 53 form the flows of air fromthe intake ports 15 to the conduit 38 and the exhaust ports 12, 13 asindicated by arrows in the figure. In addition, the flow of airgenerated by the cooling fan 51 and the flows of air generated by theair supply fans 52, 53 can be made to be airflows independent from eachother. Therefore, by driving the cooling fan 51 and the air supply fans52, 53 independently, it is possible to independently perform thecooling of the power generation unit 30 and the supply and discharge ofair to and from the power generation unit 30. The layout of the coolingfan 51 and the air supply fans 52, 53 in the fuel cell 1 in thisembodiment is not limitative; the cooling fan 51 and the air supply fans52, 53 may be so disposed as to front on opening portions formed in sidesurfaces of a plurality of power generation units so as to supply andexhaust air, whereby the supply and exhaust of air can be performedcollectively for the plurality of power generation units. Furthermore,air can be made to flow in the reverse direction by reversely rotatingthe cooling fan 51 and the air supply fans 52, 53.

The temperature sensors 61, 64, the humidity sensors 62, 65 and thetemperature sensor 63 are provided for respectively detecting thetemperature and humidity of air taken in through the intake ports 14,the temperature and humidity of air discharged through the exhaust ports12, 13, and the temperature of the power generation unit 30. Thetemperature sensor 63 is disposed in the vicinity of a roughly centralportion of the power generation unit 30, and detects the temperature ofthe power generation unit 30 at the time of power generation in thepower generation unit 30. The temperature sensor 64 and the humiditysensor 65 are disposed in the vicinity of the intake ports 14 as not toblock the conduit for the air taken in through the intake ports 14. Inaddition, the temperature sensor 61 and the humidity sensor 62 aredisposed on the air outlet side of the power generation unit 30 frontingon the air supply fans 52 and 53 so as not to hinder the flow of air.The driving of the cooling fan 51 is controlled based on the dataconcerning the temperature of the power generation unit 30 detected bythe temperature sensor 63, and the power generation unit 30 is drivenunder a preferable temperature condition. Besides, the fuel cell 1 mayinclude a pressure sensor for detecting the pressure of air supplied andexhausted, in addition to the temperature and humidity sensors.

Further, the relative humidity of the air taken in through the intakeports 14 is calculated based on the temperature and humidity detected bythe temperature sensor 64 and the humidity sensor 65, and the relativehumidity of the air discharged through the exhaust ports 12, 13 iscalculated based on the temperature and humidity detected by thetemperature sensor 61 and the humidity sensor 62. By determining thedifference between the relative humidity of the air taken in through theintake ports 15 and the relative humidity of the air exhausted throughthe exhaust ports 12, 13, it is possible to calculate the quantity ofwater discharged from the fuel cell 1. Besides, since the temperaturesensors 61, 64 and the humidity sensors 62, 65 are so disposed as not tohinder the flow of air, the power generation by the power generationunit 30 can be performed without any trouble.

Furthermore, the quantity of water produced by the power generationreaction can be calculated based on the output power generated by thepower generation unit 30. Therefore, by determining the differencebetween the quantity of water discharged from the fuel cell 1 and thequantity of water generated by the power generation reaction, it ispossible to calculate the amount of water remaining in the powergeneration unit 30. As has been described above, a stable powergeneration reaction can be performed by setting the joint bodies 32constituting the power generation unit 30 into an appropriatelymoistened state; therefore, stable power generation can be achieved bydriving the air supply fans 52, 53 on the basis of the data concerningthe amount of water remaining in the power generation unit 30. Forexample, where the amount of water remaining in the power generationunit 30 is excessively large, the rotating speeds of the air supply fans52, 53 are raised, whereby the excessive water can be discharged fromthe power generation unit 30 together with air. In addition, it ispossible not only to independently drive the cooling fan 51 forcontrolling the temperature of the power generation unit 30 and the airsupply fans 52, 53 for controlling the amount of water remaining in thepower generation unit 30 but also to make independent the flow of air bythe cooling fan 51 and the flows of air by the air supply fans 52, 53,so that the control of the amount of water remaining in the powergeneration unit 30 and the restraint of the temperature rise in thepower generation unit 30 can be performed accurately.

Further, the control of the temperature of the power generation unit 30and the amount of water remaining in the power generation unit 30 willbe described in detail, referring to FIG. 9. In the figure, the axis ofabscissas indicates the temperature of the power generation unit 30, andthe axis of ordinates indicates the amount of water remaining in thepower generation unit 30. By controlling the driving of the cooling fan51 and the air supply fans 52, 53, the temperature of the powergeneration unit 30 and the amount of water remaining in the powergeneration unit 30, which vary with time during the power generation,are controlled to within the stable region located in the vicinity ofthe center of the figure.

For example, the environmental condition represented by A in the figureis an environmental condition in which the temperature of the powergeneration unit 30 is higher and the amount of water remaining in thepower generation unit 30 is larger as compared with the environmentalcondition in the stable region, and it is necessary in the environmentalcondition A to cool the power generation unit 30 and to reduce theamount of water remaining there. In such a case, the amount of waterremaining in the power generation unit 30 is reduced by raising therotating speeds of the air supply fans 52, 53 and the power generationunit 30 is further cooled by raising the rotating speed of the coolingfan 51, whereby the temperature and the water amount are controlled fromthe environmental condition A into the stable region in which stablepower generation can be achieved.

The environmental condition represented by B in the figure is anenvironmental condition in which the temperature of the power generationunit 30 is lower and the amount of water remaining in the powergeneration unit 30 is larger as compared with the stable condition. Insuch a case, the amount of water remaining in the power generation unit30 is reduced by raising the rotating speeds of the air supply fans 52,53 and the cooling of the power generation unit 30 is suppressed bylowering the rotating speed of the cooling fan 51, whereby thetemperature of the power generation unit 30 and the amount of watertherein are controlled from the environmental condition B into thestable region in which stable power generation can be achieved.

The environmental condition represented by C in the figure is anenvironmental condition in which the temperature of the power generationunit 30 is lower and the amount of water remaining in the powergeneration unit 30 is smaller as compared with the stable condition. Insuch a case, the discharge of water produced in the power generationunit 30 is reduced by lowering the rotating speeds of the air supplyfans 52, 53 and the cooling of the power generation unit 30 issuppressed by lowering the rotating speed of the cooling fan 51. By sucha control of the driving of the air supply fans 52, 53 and the coolingfan 51, the temperature of the power generation unit 30 and the amountof water therein are controlled from the environmental condition C intothe stable region in which stable power generation can be achieved.

The environmental condition represented by D in the figure is anenvironmental condition in which the temperature of the power generationunit 30 is higher and the amount of water remaining in the powergeneration unit 30 is smaller as compared with the stable condition. Insuch a case, the discharge of water produced in the power generationunit 30 is reduced by lowering the rotating speeds of the air supplyfans 52, 53 and the power generation unit 30 is further cooled byraising the rotating speed of the cooling fan 51. By such a control ofthe driving of the air supply fans 52, 53 and the cooling fan 51, thetemperature of the power generation unit 30 and the amount of watertherein are controlled from the environmental condition D into thestable region in which stable power generation can be achieved.

By driving the air supply fans 52, 53 and the cooling fan 51 accordingto the temperature of the power generation unit 30 and the amount ofwater remaining in the power generation unit 30 in this manner, it ispossible to perform stable power generation, without causing a troublein power generation, such as dry-up.

Now, the hydrogen purge valve 54, the regulator 55 and the manual valve56 will be described below, referring to FIGS. 1, 4, 5A and 5B. As shownin FIG. 1, the hydrogen purge valve 54, the regulator 55 and the manualvalve 56 are adjacently laid out along an end face of the powergeneration unit 30. In the fuel cell 1 in this embodiment, a region forarranging various apparatuses can be secured on the end face side of thepower generation unit 30, and the apparatuses for stable driving of thefuel cell 1 can be contained in a compact form.

The hydrogen purge valve 54 as a water discharge means for dischargingthe water accumulated in the conduit 43 can discharge the water from theconduit 43 by opening to the atmosphere the discharge passage connectedto the conduit 43. When the conduit 43 is opened to the atmosphere, apressure difference is generated between the pressure exerted on thewater accumulated in the conduit 43 by the hydrogen gas on the supplypassage side and the pressure exerted by the atmospheric air on thedischarge passage side. Due to the pressure difference, the wateraccumulated in the conduit 43 is discharged from the conduit 43. Withthe pressure difference thus generated between the supply passage sideon which the hydrogen gas is supplied and the discharge passage sideopened to the atmosphere via the hydrogen purge valve 54, it is possibleto discharge water from an arbitrary conduit 43 in which water has beenaccumulated to make it difficult for the hydrogen gas to flowtherethrough, even in the case where the power generation unit 30 has astack structure; therefore, it is possible to cause the hydrogen gas toflow smoothly in the conduits 43 of all the separators 31. In addition,the hydrogen purge valve 54 can be driven by a drive system using anelectromagnetic force, for example, or electric power for driving thehydrogen purge valve 54 may be supplied from the power generation unit30.

Besides, the regulator 55 as a pressure control means for controllingthe pressure of the hydrogen gas regulates the pressure of the hydrogengas supplied from the hydrogen occlusion cartridge 60 to a requiredpressure, thereby feeding out the hydrogen gas to the power generationunit 30. For example, where the pressure of the hydrogen gas suppliedfrom the hydrogen occlusion cartridge 60 is about 0.8 to 1.0 MPa, theregulator 55 can supply the hydrogen gas to the power generation unit 30while lowering the pressure of the hydrogen gas to a pressure of about0.05 to 0.10 MPa.

Further, the manual valve 56 as a gas supply means for supplying thehydrogen gas to the power generation unit 30 opens the conduit forsupplying the hydrogen gas from the hydrogen occlusion cartridge 60 tothe power generation unit 30 at the time of performing power generationin the power generation unit 30. The hydrogen purge valve 54, theregulator 55 and the manual valve 56 are important for causing the fuelcell 1 to perform stable power generation, and these apparatuses arecontained in the fuel cell 1 in a compact form, whereby the overall sizeof the fuel cell 1 can be reduced.

Now, a specific structure of the fuel cell apparatus in this embodimentwill be described below referring to FIGS. 10 to 14. First, FIGS. 10 to12 are respectively a back view, a side view, and a face view of aseparator portion in this embodiment.

As shown in FIGS. 10 to 12, the separator 81 is provided on its backside with grooves 83 for constituting conduits for oxygen, and on itsface wide with a groove 86 for constituting a conduit for hydrogen.Incidentally, the separators 81 may be disposed with the back side onthe face side, when laminated with the power generation body (not shown)sandwiched therebetween.

As shown in FIG. 10, the separator 81 is provided in its oxygen supplyside surface with a plurality of grooves 83 extended rectilinearly inthe width direction of the separator 81, and the grooves 83 are extendedin parallel to each other, so that the grooves 83 and rib portions 82are alternately located along the longitudinal direction of theseparator 81. The length L6 in the longitudinal direction of theseparator 81 formed in a roughly flat plate-like shape is 79.5 mm, andthe width L8 orthogonal thereto is 41 mm. The grooves 83 are opened tobe wider at both end portions of the separator 81. As for specificsizes, in FIG. 10, the width L1 of a central portion extended inparallel of the groove 83 is 2 mm, and the width L2 of the rib portion82 adjacent to the groove 83 is also 2 mm. The groove 83 is opened in atapered shape at both end portions where they are wider, and the startposition L0 of the tapered portion which is formed also in the thicknessdirection of the separator 81 is 8 mm from the end portion, and thetaper is inclined at an angle of 2.15° starting from the start positionL0. At both end portions where the groove 83 is wider, the opening widthis enlarged by about 1 mm in the in-plane direction, the width L3 at theend portion of the groove 83 is 3 mm, while the width L4 of the ribportion 82 adjacent thereto is tapered to 1 mm. Plate-like bridges areincorporated at two locations in a portion, located at a distance of 5.5mm from the end portion, of the rib portion 82. Incidentally, theopening width L5 in the vicinity of the center is 2.5 mm due to theinfluence of screw holes, and the width L10 in the longitudinaldirection of a power generation body holding region continuous with theheat radiation portion 84 is 56.5 mm (see FIG. 11), and the interval L7between the screw holes is 54.5 mm.

Next, as shown in FIG. 11, as for the sizes in the thickness directionof the separator 81, the thickness T1 of the heat radiation portion 84is 1.3 mm, and the thickness T2 in the power generation holding regionwhere the grooves 83, 86 are formed is 2.3 mm.

As shown in FIG. 12, the hydrogen supply side surface 87 of theseparator 81 is provided with the groove 86 extended in a meanderingpattern for going and returning five times between a hydrogen supplyhole 89 and a hydrogen discharge hole 88, the meandering groove 86 has adepth of 0.6 mm and a width L12 of 1.0 mm, and the radius of curvatureat the turning-back portions is 0.9 mm (inside radius), 1.9 mm (outsideradius). The groove 86 becomes thinner at connection portions forconnection with the hydrogen supply hole 89 and the hydrogen dischargehole 88; the hydrogen supply hole 89 and the hydrogen discharge hole 88are sized to have a width of 1.5 mm, with the position of 2.25 mm fromthe end portion in the longitudinal direction of the separator 81 as acenter, and the start position L17 of the thinner groove from the endportion in the longitudinal direction of the separator 81 is 6 mm, sothat the length is about 3 mm. At the connection portions 90, the grooveconnected to the hydrogen supply hole 88 has a width L11 of 0.5 mm and adepth of 1.2 mm, and the groove connected to the hydrogen supply hole 89has a width of 0.5 mm and a depth of 0.3 mm. The position L15 of theconnection portion 90 on the side of the hydrogen discharge hold 88 fromthe end portion in the width direction of the separator 81 is 7.9 mm interms of center position, and the position L16 of the connection portion90 on the side of the hydrogen supply hole 89 is 33.1 mm in terms ofcenter position. Of the groove 86 extended in the meandering pattern forgoing and returning five times, the turning-back position L13 from theend portion on the side closer to the hydrogen supply hole 89 and thehydrogen discharge hole 88 in the longitudinal direction of theseparator 81 is 7 mm. Besides, the length L14 between the turning-backportions of the groove 86 is 42 mm.

Now, the structure of the fuel cell apparatus in this embodiment will bedescribed more in detail below, referring to FIGS. 13 and 14. FIG. 13 isa plan view of the fuel cell apparatus 100 in this embodiment. The fuelcell apparatus 100 has a stack structure in which the separators 81 andthe power generation bodies are stacked. In FIG. 13, the plate-likeportion disposed at the uppermost portion constituting the stackstructure is seen through, and the groove 86 formed in the surface ofthe separator in the region where the power generation unit 99 isdisposed is indicated by broken lines in the figure. The length L18obtained by summing up the size in the longitudinal direction of theseparator for forming the power generation unit 99 and the size in thelongitudinal direction of the heat radiation portion extended in thelongitudinal direction from the separator is 78 mm, and the width L8 ofthe separator is 41 mm. An end portion of a heat radiation portion 84 isrectilinear in the figure, but may be provided with notches or cutoutsfor passing wires therethrough. A casing 91 for constituting the fuelcell apparatus 100 and for containing the units inclusive of the powergeneration unit 99 has a length L21 in the longitudinal direction of95.5 mm and a width L20 of 57 mm. Since the length L21 in thelongitudinal direction and the width L20 of the casing 91 are the lengthin the longitudinal direction and the width of the fuel cell apparatus100, the fuel cell apparatus 100 in this embodiment has a length in thelongitudinal direction on plane of 93.5 mm and a width of 57 mm.

Further, the structure of the fuel cell apparatus 100 in this embodimentwill be described specifically, referring to FIG. 14. Incidentally, FIG.14 is a side view, as viewed from a lateral side, of the fuel cellapparatus 100 in the condition where the casing 91 has been removed. Thepower generation unit 99 has a stack structure in which nine separators81 are stacked, with the power generation bodies 96 sandwichedtherebetween, and has a structure in which eight power generation cellsare connected in series with each other. The power generation unit 99 isdisposed on a base 98 which constitutes a bottom portion of the fuelcell apparatus 100. The height T4 from the bottom surface of the base 98to the surface of a plate-like portion disposed at the uppermost portionof the power generation unit 99 is 34.62 mm. In addition, the height T5from the bottom surface of the base 98 to the center in the thicknessdirection of the separator 81 located at a central portion of the powergeneration unit 99 is 17.78 mm, which is approximately equal to theheights from the bottom surface of the base 98 to the centers of acooling fan 92 and air supply fans 93, 94 disposed on the side of a sidesurface of the power generation unit 99. The height T6 of the powergeneration unit 99 obtained by summing up the thickness of theplate-like portion 97, and the stacked separators 81 and powergeneration bodies 96 is 29.62 mm. The height of the cooling fan 92 isapproximately equal to the height between the heat radiation portion 84disposed at the uppermost portion of the power generation unit 99 andthe heat radiation portion 84 disposed at the lowermost portion, so thatair for cooling can be supplied to the entire part of the heat radiationportions 84. The height of the air supply fans 93, 94 is approximatelyequal to the height between the grooves 82 at the uppermost portion ofthe power generation unit 99 and the grooves 82 at the lowermostportion, so that oxygen-containing air can be sufficiently supplied tothe entire part of the grooves 82.

As has been described above, the fuel cell according to the presentinvention can contain in a compact form the various apparatuses fordriving the fuel cell, and is preferable for use as a power source forsupplying electric power for driving a portable electronic apparatussuch as a notebook type personal computer, a cellular phone and a PDA.In addition, the application of the fuel cell 1 according to the presentinvention is not limited to these portable electronic apparatuses, andthe fuel cell 1 can be utilized as a power source for driving variouselectronic apparatuses.

INDUSTRIAL APPLICABILITY

According to the fuel cell of the present invention in an embodiment, byperforming restraint of the temperature rise in the power generationunit and control of the amount of water remaining in the powergeneration unit, it is possible to achieve stable power generationwithout causing a trouble in power generation, such as dry-up. Further,the control of the temperature of the power generation unit and thecontrol of the amount of water remaining in the power generation unitcan be independently performed accurately, so that it is possible toprovide a fuel cell which is high in reliability. In addition, accordingto such a fuel cell, various apparatuses for performing power generationcan be contained in the fuel cell in a compact form, so that the fuelcell can be reduced in size.

Furthermore, according to the electronic apparatus of the presentinvention in an embodiment, driving by a fuel cell can be achieved evenfor a portable electronic apparatus by mounting thereon the fuel cellsized for portable use, and the fuel cell can be mounted on a requiredelectronic apparatus.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present invention andwithout diminishing its intended advantages. It is therefore intendedthat such changes and modifications be covered by the appended claims.

1-41. (canceled)
 42. A fuel cell comprising: a power generation unitprovided with a conduit for an oxidant gas containing at least oxygen; aheat radiation unit connected to said power generation unit so as toradiate heat from said power generation unit; a gas flow means forcausing said oxidant gas to flow in said conduit; and a cooling meansdriven independently from said gas flow means so as to cool said heatradiation unit.
 43. The fuel cell as set forth in claim 42, wherein saidpower generation unit comprises: a joint body including a conductorhaving ionic conductivity and electrodes opposed to each other with saidconductor therebetween; and a plurality of separators for clamping saidjoint body therebetween.
 44. The fuel cell as set forth in claim 43,wherein said conductor includes a proton conductor.
 45. The fuel cell asset forth in claim 43, wherein said separators each have a heat transferportion extending from an inside of said separator to said heatradiation unit.
 46. The fuel cell as set forth in claim 43, wherein saidseparators each have a water suction means for suctioning and removingwater from said conduit.
 47. The fuel cell as set forth in claim 43,wherein said power generation unit has a stack structure in which saidjoint body and said separators are laminated.
 48. The fuel cell as setforth in claim 47, wherein said separators each have an in-plane conduitfor supplying a fuel into a plane where said separator and said jointbody make contact with each other.
 49. The fuel cell as set forth inclaim 47, wherein said separators each have a supply hole for supplyingthe fuel into said in-plane conduit, and a discharge hole fordischarging the fuel from said in-plane conduit.
 50. The fuel cell asset forth in claim 49, wherein between the adjacent separators, saidsupply holes are connected to each other to form a supply passage forsupplying the fuel to said separators, and said discharge holes areconnected to each other to form a discharge passage for discharging thefuel from said separators.
 51. The fuel cell as set forth in claim 48,wherein the sectional area of a connection portion where said in-planeconduit is connected to said supply passage is smaller than thesectional area of said in-plane conduit.
 52. The fuel cell as set forthin claim 48, wherein the sectional area of a connection portion wheresaid in-plane conduit is connected to said discharge passage is smallerthan the sectional area of said in-plane conduit.
 53. The fuel cell asset forth in claim 48, wherein the sectional area of a connectionportion where said in-plane conduit is connected to said supply passageis smaller than the sectional area of a connection portion where saidin-plane conduit is connected to said discharge passage.
 54. The fuelcell as set forth in claim 48, further comprising a water dischargemeans for discharging water from said in-plane conduit by generating adifference in pressure on said water between the supply passage side andthe discharge passage side, in said in-plane conduit in which said wateris accumulated.
 55. The fuel cell as set forth in claim 52, wherein saidwater discharge means opens a part of said discharge passage to theatmosphere so as to generate said pressure difference and thereby todischarge said water from said in-plane conduit.
 56. The fuel cell asset forth in claim 42, wherein said cooling means causes a gasstagnating in proximity of at least said heat radiation unit to flow soas to release heat from said heat radiation unit.
 57. The fuel cell asset forth in claim 42, further comprising detection means for detectingan environmental condition for controlling driving of said gas flowmeans and said cooling means.
 58. The fuel cell as set forth in claim57, wherein said detection means detects at least one of temperature andhumidity as said environmental condition.
 59. The fuel cell as set forthin claim 57, wherein said detection means are arranged at respectivepositions so as to be capable of detecting the temperature and humidityof said oxidant gas supplied to said power generation unit, thetemperature and humidity of said oxidant gas discharged from said powergeneration unit, and the temperature of said power generation unit. 60.The fuel cell as set forth in claim 57, further comprising a controlsubstrate supporting thereon a control circuit for controlling drivingof at least said gas flow means and said cooling means based on saidenvironmental condition.
 61. The fuel cell as set forth in claim 57,wherein the driving of said gas flow means and said cooling means iscontrolled according to the amount of water remaining in said powergeneration unit which is calculated based on said environmentalcondition and the quantity of electric power generated by said powergeneration unit.
 62. The fuel cell as set forth in claim 42, furthercomprising a fuel supply means for supplying the fuel for reaction withsaid oxidant gas from a fuel storage unit to said power generation unitat the time of driving said power generation unit.
 63. The fuel cell asset forth in claim 42, further comprising a pressure control means forcontrolling a pressure of the fuel supplied to said power generationunit.
 64. A fuel cell comprising: a power generation unit provided in aside surface with an opening portion of a conduit for an oxidant gascontaining at least oxygen; and a heat radiation unit connected to saidpower generation unit so as to radiate heat from said power generationunit; wherein a gas flow means for causing said oxidant gas to flow insaid conduit is disposed along the side surface of said power generationunit, and a cooling means for cooling said heat radiation unit isdisposed along said side surface adjacent to said gas flow means. 65.The fuel cell as set forth in claim 64, wherein said fuel cell has acasing for covering at least said power generation unit, said heatradiation unit, said gas flow means, and said cooling means.
 66. Thefuel cell as set forth in claim 64, wherein said gas flow means suctionsin said oxidant gas through said opening portion and discharges saidoxidant gas through a first exhaust port provided in said casing so asthereby to cause said oxidant gas to flow in said conduit.
 67. The fuelcell as set forth in claim 65, wherein said gas flow means suctions saidoxidant gas into said fuel cell through a first intake port provided insaid casing to thereby form a flow of said oxidant gas independent ofthe flow of said oxidant gas generated by said cooling means.
 68. Thefuel cell as set forth in claim 67, wherein said first intake port isprovided at a position opposed to said first exhaust port, and said gasflow means is disposed between said first intake port and said firstexhaust port.
 69. The fuel cell as set forth in claim 65, wherein saidcooling means discharges said oxidant gas through a second exhaust portprovided in said casing to thereby cause said oxidant gas to flow inproximity of said heat radiation unit.
 70. The fuel cell as set forth inclaim 65, wherein said cooling means suctions said oxidant gas into saidfuel cell through a second intake port provided in said casing.
 71. Thefuel cell as set forth in claim 70, wherein said second intake port isprovided at a position opposed to said second exhaust port, and saidcooling means is disposed between said second intake port and saidsecond exhaust port.
 72. The fuel cell as set forth in claim 64, whereinsaid opening portion is tapered so that it becomes narrower along adepth direction of said conduit for said oxidant gas.
 73. The fuel cellas set forth in claim 64, wherein an opening width of said openingportion is greater than the conduit width of said conduit for saidoxidant gas.
 74. The fuel cell as set forth in claim 73, wherein saidopening width is broader than said conduit width along at least one of asideways direction and the longitudinal direction.
 75. The fuel cell asset forth in claim 64, further comprising detection means for detectingan environmental condition for controlling the driving of said gas flowmeans and said cooling means.
 76. The fuel cell as set forth in claim75, wherein said detection means detects at least one of temperature andhumidity as said environmental condition.
 77. The fuel cell as set forthin claim 75, wherein said detection means are arranged at respectivepositions so as to be capable of detecting the temperature and humidityof said oxidant gas supplied to said power generation unit, thetemperature and humidity of said oxidant gas discharged from said powergeneration unit, and the temperature of said power generation unit. 78.The fuel cell as set forth in claim 75, further comprising a controlsubstrate supporting thereon a control circuit for controlling thedriving of at least said gas flow means and said cooling means based onsaid environmental condition.
 79. The fuel cell as set forth in claim64, wherein a water discharge means for discharging water from saidconduit for the fuel supplied to said power generation unit for reactionwith said oxidant gas is disposed along an end face of said powergeneration unit.
 80. The fuel cell as set forth in claim 79, wherein afuel supply means for supplying said fuel from a fuel storage unit tosaid power generation unit at the time of driving said power generationunit is disposed along an end face of said power generation unit.
 81. Anelectronic apparatus comprising a fuel cell, said fuel cell comprising:a power generation unit provided with a conduit for an oxidant gascontaining at least oxygen; a heat radiation unit connected to saidpower generation unit so as to radiate heat from said power generationunit; a gas flow means for causing said oxidant gas to flow in saidconduit; and a cooling means driven independently of said gas flow meansso as to cool said heat radiation unit; wherein said electronicapparatus is driven by being supplied with electric power from said fuelcell.
 82. An electronic apparatus comprising a fuel cell, said fuel cellcomprising: a power generation unit provided in a side surface with anopening portion of a conduit for an oxidant gas containing at leastoxygen; and a heat radiation unit connected to said power generationunit so as to radiate heat from said power generation unit; wherein agas flow means for causing said oxidant gas to flow in said conduit isdisposed along the side surface of said power generation unit, and acooling means for cooling said heat radiation unit is disposed alongsaid side surface adjacently to said gas flow means, wherein saidelectronic apparatus is driven by being supplied with electric powerfrom said fuel cell.